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From: Andrew Morton <akpm@linux-foundation.org>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
	linux-arch@vger.kernel.org, Will Deacon <will@kernel.org>,
	Dave P Martin <Dave.Martin@arm.com>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Szabolcs Nagy <szabolcs.nagy@arm.com>,
	Kevin Brodsky <kevin.brodsky@arm.com>,
	Andrey Konovalov <andreyknvl@google.com>,
	Peter Collingbourne <pcc@google.com>,
	Steven Price <steven.price@arm.com>
Subject: Re: [PATCH v5 06/25] mm: Add PG_ARCH_2 page flag
Date: Wed, 24 Jun 2020 11:33:07 -0700	[thread overview]
Message-ID: <20200624113307.6165b3db2404c9d37b870a90@linux-foundation.org> (raw)
In-Reply-To: <20200624175244.25837-7-catalin.marinas@arm.com>

On Wed, 24 Jun 2020 18:52:25 +0100 Catalin Marinas <catalin.marinas@arm.com> wrote:

> From: Steven Price <steven.price@arm.com>
> 
> For arm64 MTE support it is necessary to be able to mark pages that
> contain user space visible tags that will need to be saved/restored e.g.
> when swapped out.
> 
> To support this add a new arch specific flag (PG_ARCH_2) that arch code
> can opt into using ARCH_USES_PG_ARCH_2.
> 
> ...
>
> --- a/fs/proc/page.c
> +++ b/fs/proc/page.c
> @@ -217,6 +217,9 @@ u64 stable_page_flags(struct page *page)
>  	u |= kpf_copy_bit(k, KPF_PRIVATE_2,	PG_private_2);
>  	u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE,	PG_owner_priv_1);
>  	u |= kpf_copy_bit(k, KPF_ARCH,		PG_arch_1);
> +#ifdef CONFIG_ARCH_USES_PG_ARCH_2
> +	u |= kpf_copy_bit(k, KPF_ARCH_2,	PG_arch_2);
> +#endif

Do we need CONFIG_ARCH_USES_PG_ARCH_2?  What would be the downside to
giving every architecture a PG_arch_2, but only arm64 uses it (at
present)?



  reply	other threads:[~2020-06-24 18:33 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-24 17:52 [PATCH v5 00/25] arm64: Memory Tagging Extension user-space support Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 01/25] arm64: mte: system register definitions Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 02/25] arm64: mte: CPU feature detection and initial sysreg configuration Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 03/25] arm64: mte: Use Normal Tagged attributes for the linear map Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 04/25] arm64: mte: Add specific SIGSEGV codes Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 05/25] arm64: mte: Handle synchronous and asynchronous tag check faults Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 06/25] mm: Add PG_ARCH_2 page flag Catalin Marinas
2020-06-24 18:33   ` Andrew Morton [this message]
2020-06-24 18:36     ` Matthew Wilcox
2020-06-25 17:10       ` Catalin Marinas
2020-07-01 17:30     ` Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 07/25] arm64: mte: Clear the tags when a page is mapped in user-space with PROT_MTE Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 08/25] arm64: mte: Tags-aware copy_{user_,}highpage() implementations Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 09/25] arm64: Avoid unnecessary clear_user_page() indirection Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 10/25] arm64: mte: Tags-aware aware memcmp_pages() implementation Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 11/25] mm: Introduce arch_calc_vm_flag_bits() Catalin Marinas
2020-06-24 18:36   ` Andrew Morton
2020-06-25 17:34     ` Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 12/25] arm64: mte: Add PROT_MTE support to mmap() and mprotect() Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 13/25] mm: Introduce arch_validate_flags() Catalin Marinas
2020-06-24 18:37   ` Andrew Morton
2020-06-24 17:52 ` [PATCH v5 14/25] arm64: mte: Validate the PROT_MTE request via arch_validate_flags() Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 15/25] mm: Allow arm64 mmap(PROT_MTE) on RAM-based files Catalin Marinas
2020-06-24 18:42   ` Andrew Morton
2020-06-24 17:52 ` [PATCH v5 16/25] arm64: mte: Allow user control of the tag check mode via prctl() Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 17/25] arm64: mte: Allow user control of the generated random tags " Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 18/25] arm64: mte: Restore the GCR_EL1 register after a suspend Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 19/25] arm64: mte: Add PTRACE_{PEEK,POKE}MTETAGS support Catalin Marinas
2020-06-25 17:10   ` Luis Machado
2020-07-01 17:16     ` Catalin Marinas
2020-07-01 17:32       ` Luis Machado
2020-07-03 13:18         ` Catalin Marinas
2020-07-03 10:50     ` Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 20/25] fs: Handle intra-page faults in copy_mount_options() Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 21/25] mm: Add arch hooks for saving/restoring tags Catalin Marinas
2020-06-24 18:45   ` Andrew Morton
2020-06-25  9:04     ` Steven Price
2020-06-25 12:09       ` Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 22/25] arm64: mte: Enable swap of tagged pages Catalin Marinas
2020-06-25 11:37   ` Steven Price
2020-06-25 11:59     ` Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 23/25] arm64: mte: Save tags when hibernating Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 24/25] arm64: mte: Kconfig entry Catalin Marinas
2020-06-24 17:52 ` [PATCH v5 25/25] arm64: mte: Add Memory Tagging Extension documentation Catalin Marinas
2020-06-25 12:22   ` Szabolcs Nagy
2020-06-26 14:54     ` Catalin Marinas

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